1) A point charge is placed at the centre of a spherical Gaussian surface. Is ΦE changed,
a) if the surface is replaced by a cube of the same volume?
b) if the charge is moved off centre in the original sphere, still remaining inside?
2) A point charge q is placed at the centre of a cube of edge a. What is the flux through each of the cube faces? A point charge q is placed at one corner of a cube of edge a. What is the flux through each of the cube faces?
The attempt at solution
1) a) E remains same as the charge is not changed in magnitude. Surface area of the cube is different, Φ=Edscosθ
So ds being different ΦE will change.
b) If we consider the sphere to be our Gaussian surface, the charge enclosed does not change in its magnitude. Hence no change in ΦE
2) ΦE = q/6ε for both the cases as E,ds,q all remain same in both cases.
1) a) and 2) second part is wrong. Please explain.